wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

26-10 Industrial Communication Systems
to their excellent qualification for refurbishment but also their reduced complexity compared to wired
systems. The two most well-known wireless protocols for home automation are IEEE 802.15.4/ZigBee
[24] and KNX RF [19]. While the latter is conceived as the wireless extension of the established open
KNX protocol, especially ZigBee was designed with a broad focus on industrial, building, and home
automation (in this order). However, ZigBee has not yet achieved a breakthrough in the residential automation
market, most obviously due to very limited availability of commercial products. To tackle this
shortcoming, in November 2007, the ZigBee alliance published the ZigBee home automation profile. It
provides both product manufacturers and end users with standardized device templates, thus guaranteeing
specific functionalities and ensuring interoperability of certified devices at the same time.
With EnOcean [16], the concept of energy harvesting was commercially exploited for the first time.
Energy-autarkic devices employ the EnOcean technology to gather enough energy from the environment
(by means of solar cells, piezoelectric elements, thermocouples) to perform computations within
the node and set off telegrams over the air. In order to get by with the small amount of energy at disposition,
the EnOcean protocol is tailored for lowest possible power consumption. Featuring a comparably
high data rate and a small telegram size, EnOcean achieves very short transmission durations, therefore
encountering a lower statistical probability for telegram collisions. This robustness, in turn, increases
the protocol scalability (more nodes may send simultaneously) and reduces power consumption (less
frequent telegram retransmissions). Because of its limited set of functions, EnOcean is often employed
in combination with other systems, for example, KNX (RF) or ZigBee, to fully exploit the benefits of
both wireless and battery-less technologies.
The Z-Wave [25] protocol was developed with an explicit focus on home control applications. With
low data rate communication and a device count limited to 232 devices, applications for lighting, home
access control, entertainment systems, and household appliances are serviced. Z-Wave devices can be
roughly classified into controllers and slaves devices. The latter only act upon messages, while controllers
are aware of the network topology and all devices belonging to the network. Therefore, they can
perform more complex automation control and provide routing and security services in the network.
With the set up of Z-Wave networks being easy and the control of the automation functions intuitive,
Z-Wave is often chosen for scenarios involving less technology-experienced users that do not require
extensive configuration, management, or visualization possibilities.
Especially in HAS, the interaction among multiple systems, which always has to be seen under the
importance of usability, is a key asset. Since these systems are diverse and not only cover the historic
core domains HVAC and lighting/shading but also consumer electronics (brown ware) to home appliances
(white ware), integration in the home has special requirements. Several technologies that support
the transition toward a smart home are discussed in the following paragraphs.
Universal Plug and Play (UPnP) [23] provides a set of open IP-based protocols and mechanisms
to easily integrate and control devices in a peer-to-peer network (zero-configuration networking).
While UPnP has initially been developed for Windows to enable plug and play for PC peripherals,
it has now become a widely accepted, powerful and yet simple approach to connect and control
Internet gateways and multimedia devices in homes. UPnP is media and device independent.
The standard is hosted by the UPnP forum, an organization with several hundred members across
industry. The UPnP device architecture covers IP addressing (DHCP or APIPA), device and service
discovery (SSDP), description (XML), control (HTTP/SOAP), eventing (GENA), and presentation
(URL/HTML). At the top level, specifications for standardized device classes, the “device control
protocols” (DCPs), are specified. The DCPs, which are developed and maintained by the UPnP forum,
define a common interface that allows vendor-independent easy handle access to UPnP DCP compliant
devices. Currently, DCPs have been defined for media servers and renderers, printers, Internet
gateways, HVAC, and lighting devices.
The Chinese standard for Intelligent Grouping and Resource Sharing (IGRS) [18] defines a software
architecture similar to the one known from UPnP. It builds upon the three goals intelligent grouping,
which allows devices to discover available services; resource sharing, which makes resources of
© 2011 by Taylor and Francis Group, LLC